Magnetic fields have long been used for the treatment of physical injuries and chronic pain. Early magnetic therapy involved the use of static magnetic fields produced by permanent magnets incorporated into items such as bracelets, belts, back pads, mattress pads and mattresses. It is believed that static magnetic fields have some efficacy in the treatment of broken bones and soft tissue injuries, and tend to promote the circulation of blood as well as relieve stiffness in muscles. The effectiveness of such treatments in human and veterinary applications has been the subject of debate.
More recent attempts to employ the therapeutic effects of magnetic fields have focused on devices which generate an electromagnetic field, and the methods of treatment employing such devices. Although a variety of designs have been proposed in the prior art, electromagnetic devices generally comprise a power supply coupled to a circuit capable of producing an AC or DC output which is transmitted to an inductor coil. One form of inductor coil consists of a number of wire windings wrapped about a coil body with an open or air center, or, alternatively, a ferrous core wrapped with wire windings. In response to the output from the circuit, an electromagnetic field is generated by the inductor coil which is then directed toward the area(s) of the body of a patient to be treated.
In many instances, the circuit of electromagnetic devices produces a pulsed or time-varying output in the shape of a square wave, sine wave, triangular wave or the like. Such output can be at essentially any selected frequency and voltage. A pulsed output from the circuit results in the production of a time-varying or pulsed magnetic field by the inductor coil. If the circuit emits an AC signal, the position of the north and south poles of the resulting magnetic field from the inductor coil changes with each cycle, whereas a DC output produces an electromagnetic field in which the position of the magnetic poles remains constant.
The application of the general concepts of the formation of electromagnetic fields noted above to the treatment of physical and mental disorders has resulted in a widely varying array of devices and treatment methods. Prior art devices operate at completely different ends of the spectrum in terms of field strength and frequency. The predominant approach appears to follow the adage that “more is better.” U.S. Pat. Nos. 6,425,852; 6,132,361; 5,813,970 and 5,769,778, for example, teach electromagnetic devices which produce a magnetic field having a flux density in range of up to 10,000 to 20,000 gauss. Devices of this type are used for therapies such as transcranial magnetic brain stimulation for the treatment of neurological and mental disorders. On the other end of the spectrum, devices have been developed for the treatment of various conditions using a magnetic field having a flux density in the range of 10 nanogauss to 10 milligauss, applied at frequencies in the range of 0 to 1000 Hz. See, for example, U.S. Pat. Nos. 6,099,459 and 5,496,258.
There appears to be no consensus whatsoever as to what flux density levels or frequencies should be employed in electromagnetic therapy. Although proposed as a non-invasive alternative to pharmacological and nutritional solutions, it is believed that electromagnetic therapy conducted at the high flux density and/or high frequency levels noted above may, in fact, be harmful whereas treatment at the lower end of the spectrum as suggested in U.S. Pat. No. 6,099,459 will have little, if any, therapeutic effect without extensive technical expertise. None of these treatment methods are reflective of the magnetic field density levels and frequencies which occur naturally within a patient, or are produced naturally within the ionosphere and by the earth.
Other significant limitations of many prior art therapeutic electromagnetic devices is their lack of portability, their complexity and the need for relatively skilled medical personnel to operate them effectively. For example, U.S. Pat. Nos. 6,280,376; 6,099,459; 6,210,317 and application U.S. 2002/0103411 disclose devices which are not portable and require a skilled technician or physician to operate. In order to receive treatment, patients must undertake the time and expense of traveling to the office where the machine is located during normal business hours. Other devices, while they may be more portable, permit a relatively wide range of adjustment of field strength and/or frequency. Allowing patients and practitioners to control these parameters, even with prior instruction, can lead to ineffective or potentially harmful treatment.